Driven Vane Compressor

ABSTRACT

A rotary vane device comprising a rotor and a vane positioned in a pumping chamber in a housing for rotation about respective eccentric axes, wherein the rotor has a rotor slot in which the vane is positioned, characterized by the vane being driven and the rotor following the vane.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/736,959 filed Nov. 15, 2005, which is hereby incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to rotary vane machines and, moreparticularly, to a rotary vane machine wherein the vane is driven ratherthan the rotor.

BACKGROUND OF THE INVENTION

Rotary vane machines are distinguished from virtually all other fluiddisplacement machines in their remarkable simplicity. The operatingefficiency of such machines, however, is negatively impacted by machinefriction. Friction in non-guided rotary vane machines can arise from therubbing of the tip of the sliding vane against the inner contour of thestator wall. Governing the motion of the vane by the stator wall contouralso can inhibit the area through which fluid can enter or exit themachine. This can result in increased fluid flow pressure losses in theinlet and outlet port regions.

Over the years, proposals have been made to move the vanes radiallyother than through the direct action of the vane tips rubbing along theinside casing or stator wall. Prior attempts have focused upon the useof wheels or rollers pinned to the sides of the vanes wherein theserollers follow a circular or non-circular track of an appropriateconfiguration. The cooperation of the rollers in the roller guide trackcontrols the radial location of the vane which is pinned to the rollerfollower and hence determines the position of the tip of the vane.

Another known and advantageous fluid-handling device employs a singlevane. In essence, this single vane device operates in a manner similarto most conventional vane compressors, with two key exceptions: therotor incorporates only a single slot for the simple vane, and that vanedoes not contact the housing while the rotor is spinning. Instead, anextremely thin air gap exists between the vane tip and the stator wall.In operation, air enters through a port on one side of the unit and iscompressed by the front side of the vane. The vane's rear side,meanwhile, draws gas into the housing.

SUMMARY OF THE INVENTION

In contrast to the above-mentioned single vane and other rotary vanedevices, the present invention provides a rotary vane device wherein thevane is rotatably driven rather than the rotor. This has been found tobeneficially reduce the side load acting on the vane, essentially towhatever is the bearing drag acting on the rotor that is rotatablydriven by the vane. Benefits arising from the invention include lesspower consumption, longer life, fewer stack-up tolerances between thevane and housing, the ability to use plastic for the rotor and vane dueto the reduced loads, and/or fewer components.

Accordingly, the invention provides a rotary vane device comprising arotor and a vane positioned in a pumping chamber in a housing, whereinthe rotor has a rotor slot in which the vane is positioned,characterized by the vane being driven and the rotor following the vane.

More particularly, the rotary vane device comprises a housing includinga pumping chamber having an axis and flow passages for flow of fluid toand from the pumping chamber. A rotor is eccentrically positioned in thepumping chamber and supported in the housing for rotation about an axiseccentric to the pumping chamber axis whereby a variable volume space isformed between a radially outer surface of the rotor and a radiallyinner surface of the housing. The rotor has a radially extending slotopening to the radially outer surface of the rotor, and a vane drivemember is supported in the housing for rotation about the pumpingchamber axis. A vane is disposed in the rotor slot and coupled to thevane drive shaft independently of the rotor for rotation with the vanedrive member about the pumping chamber axis. The vane has a radiallyouter end adjacent the radially inner surface of the housing and a sidewall for engaging an opposed side wall of the rotor slot whilepermitting relative radial movement between the vane and the rotor slot,whereby rotation of the vane about the chamber axis will rotatably drivethe rotor about the rotor axis within the chamber while the vane movesradially relative to rotor.

The vane drive member may include a drive shaft coaxial with the pumpingchamber axis, and the vane may be fixedly joined to the shaft for radialextension away from the shaft.

The rotor slot may increase in width going from a radially outer end ofthe slot to a radially inner end of the slot, for accommodating relativepivotal movement of the vane relative to the side wall of the slot whenthe vane is rotatably driven about the pumping chamber axis.

The vane may be attached to the drive shaft by a pair of axially spacedapart vane supports fixed to the drive shaft for rotation with the driveshaft, and the vane may extend axially between the vane supports. Thehousing may have axially spaced apart side walls defining respectiveaxial ends of the pumping chamber, and the drive shaft may have oppositeaxial ends supported by bearings in the side walls, respectively. Thevane may be radially outwardly spaced from the drive shaft for massreduction purposes.

The housing may include a stator plate having a through bore forming thepumping chamber, and opposite end plates may close the ends of thepumping chamber.

The radially inner surface of the housing preferably is curvedconcentrically around the pumping chamber axis, and the radially outersurface of the rotor preferably is curved concentrically around therotor axis.

A seal member may be provided at the radially outer end of the vane forsealingly engaging the radially inner surface of the housing.

The rotor may have opposite ends thereof supported by respectivebearings in the housing. Each bearing may include an inner race, anouter race and anti-friction elements between the inner and outer races.

The vane and rotor may be about equal in longitudinal length, and theymay be rotationally (dynamically) balanced.

The radially outer end of the vane may be convexly curved concentricallywith the pumping chamber axis.

Further features of the invention will become apparent from thefollowing detailed description when considered in conjunction with thedrawings.

BRIEF DESCRIPTION OF DRAWINGS

In the annexed drawings:

FIG. 1 is a perspective view of a rotary vane device in accordance withthe invention;

FIG. 2 is a perspective view of the rotary vane device of FIG. 1, butwith an end plate removed to show interior components of the deviceincluding bearing elements;

FIG. 3 is a perspective view similar to FIG. 2, but with bearingelements removed;

FIG. 4 is a perspective view similar to FIG. 3, but with a rotor endmember removed from the rotor body to show an end of a vane and drivemember assembly;

FIG. 5 is an end elevational view of the rotary vane device of FIG. 1,with the end plate removed to show interior components of the deviceincluding bearing elements;

FIG. 6 is a perspective view of the vane and drive member assembly; and

FIGS. 7-10 are views similar to FIG. 4, but shown in end elevation withthe vane and drive member assembly shown at relatively rotatedpositions.

DETAILED DESCRIPTION

Referring now to the drawings in detail, and initially to FIGS. 1-5, anexemplary rotary vane device according to the invention is designatedgenerally by reference numeral 20. As shown, the device 20 generallycomprises a housing 21, a rotor 22 (FIGS. 3 and 4) and a vane and driveassembly 23 (FIGS. 4 and 6). In the illustrated embodiment, the vane anddrive assembly 23, as best seen in FIG. 6, comprises a single vane 26mounted, or formed integrally with, a vane drive member 27. Althoughthese components will be described below in greater detail, it will beappreciated that such components can vary in various respects withoutdeviating from the basic principles of the present invention. Inaddition, the illustrated rotary vane device is particularly suited foruse as a gas compressor and will be chiefly described in this context. Arotary vane device according to the invention, however, may be adaptedfor use with other fluids, in particular as a pump for liquids.Additionally, as is typical of many conventional compressors and pumps,the rotary vane device 20 can be reversely operated as a motor, wherepressurized fluid is supplied to the device to effect rotation of thevane 26 to output a rotary motion. Those skilled in the art will readilyappreciate the reversibility of the operation of the rotary vane device.

Turning now to details of the various components, the housing 21includes a pumping chamber 30 having an axis 31 and ports formed byinlet/outlet port members 34 and 35 for flow of fluid to and from thepumping chamber. The ports can be positioned in a conventional mannerfor supplying fluid to the pumping chamber and discharging pressurizedfluid from the pumping chamber when operating as a compressor or pump,or conversely when operating as a motor.

Preferably the housing 21 is assembled from several components. Asshown, the housing 21, which may be supported by a bracket 37, includesa stator plate (block) 38 having a through bore forming the pumpingchamber 30, and opposite end (cover) plates 40 and 41 that close theends of the through bore. The through bore is bounded by a radiallyinner surface 42 of the housing that preferably is curved concentricallyaround the pumping chamber axis, as is typical of known rotary vane typedevices. The stator and end plates may be assembled together and securedto one another by suitable fasteners, such as the illustrated screws 43.In the illustrated embodiment, the cylindrical wall of the stator plate38 is provided with two openings that are covered by the port members 34and 35.

The rotor 22 is eccentrically positioned in the pumping chamber 30 andsupported in the housing 21 by bearings for rotation about an axis 49eccentric to the pumping chamber axis 31 whereby a variable volume spaceis formed between a radially outer surface 50 of the rotor and theradially inner surface 42 of the housing. Preferably, the radially outersurface of the rotor is curved concentrically around the rotor axis.That is, the rotor is in the form of a right cylindrical body.

As above noted, the rotor 22 is supported by bearings in the housing 21.One such bearing is indicated at 53 in FIGS. 2 and 5, the bearing 53having been removed in FIGS. 3 and 4. Although any suitable bearing maybe employed, the bearing 53 includes an inner race 54 and an outer race55 with a plurality of anti-friction elements, such as ball bearings,interposed therebetween. The inner race 54 is fitted on a tubular stubshaft 56 (FIG. 3) projecting from the rotor 22. In the illustratedembodiment, the stub shaft is provided on a rotor end member 57 fastenedto an axial end of a rotor body 58 by suitable means, such as thefasteners 59. The outer race is received in a correspondingly sizedpocket formed in the end plate 40 of the housing. A similar arrangementis provided at the other end of the rotor. The bearings 53 provide foressentially friction-free rotation of the rotor in the pumping chamberabout the rotor axis 49.

The rotor 22, at its top as shown in FIG. 5, is in near contact with theinner surface 42 of the stator plate 38. This provides a non-contactseal between the rotor and the inner surface of the stator plate at alocation between the inlet/outlet ports 34 and 35, thereby isolating onefrom the other although some leakage may occur. Consequently, the radiusof the rotor plus the offset is only slightly less than the radius ofthe pumping chamber 30 so that no contact will occur while stillminimizing any leakage between the rotor and the inner surface of thebore. On the other hand, the radius of the rotor should not be greaterthan the radius of the pumping chamber less offset between the pumpingchamber axis and the rotor axis. Otherwise the outer surface of therotor would engage the inner housing surface and preclude rotation ofthe rotor.

The rotor 22 also is provided with a radially extending vane slot 68opening to the radially outer surface of the rotor as best seen in FIG.4. In the illustrated embodiment, the slot 16 extends the entirelongitudinal length of the rotor body 58 which in turn is equal in widthof the pumping chamber 30, except for provision of necessary clearancesto allow rotation of the rotor in the pumping chamber. Because the slotreduces the mass of the rotor on the side containing the slot, the otherside may have material removed to dynamically balance the rotor, asdesired.

The slot 68 in the rotor 22 is configured to receive the vane 26, whichmay have generally parallel side walls and a longitudinal lengthessentially the same as the longitudinal length of the rotor body 58. Inthe illustrated embodiment, the vane is integrally formed as part of thevane and drive assembly 23. The vane and drive assembly, as best seen inFIG. 6, further comprises a drive shaft (axle) 69 that is supported ateach end by a respective bearing 71 in the housing for rotation aboutthe pumping chamber axis 31. Although any suitable bearing may beemployed, the bearing 71 includes an inner race and an outer race with aplurality of anti-friction elements, such as ball bearings, interposedtherebetween. The inner race is fitted on a reduced diameter end portion72 of the shaft. The outer race is received in a correspondingly sizedpocket formed in the end plate 40 of the housing 21. The bearing 71 isaxially outwardly spaced in relation to the bearing 53 that rotatablysupports the rotor stub shaft 56. The bearing 71 and 53 will also beradially offset from one another to provide the offset between the rotoraxis 49 and the pumping chamber axis 31. A similar arrangement isprovided at the other end of the vane shaft 69.

The vane 26 preferably is fixedly joined to the drive shaft 69 forradial extension away from the shaft. As shown in FIG. 6, the vane maybe attached to the drive shaft by a pair of axially spaced apart vanesupports 75 and 76 fixed to the drive shaft for rotation with the driveshaft, and the vane may extend axially between the vane supports. Thevane may be radially outwardly spaced from the drive shaft, particularlyfor mass reduction purposes. The vane preferably is dynamically balancedand to this end a counterweight 77 may be assembled between the vanesupports diametrically opposite the vane.

The vane 26 preferably has a radial length such that its radially outerend is in near contact with the inner surface 42 of the stator plate 38.That is, the outer end (or tip) of the vane is spaced from the innersurface 42. This provides a non-contact seal between the vane and theinner surface 42. Opposite sides of the vane when projecting from therotor form respective ends of variable volume spaces between the rotorand inner surface of the stator plate, although some leakage may occurthrough the small gap between the vane end and inner surface of thestator plate. The radially outer end of the vane may be convexly curvedconcentrically with the pumping chamber axis 31. A clearance between thevane tip and the inner surface 42 surrounding the stator bore, in therange of 0.002 inches to 0.004 inches, has been found to providedesirable operating results while still permitting relatively low costfor manufacture of the unit. The same clearance can be provided betweenthe top of the rotor 22 and the inner surface 42.

At its radially outer end, side walls of the vane 26 are positionedadjacent and for sliding engagement with respective side walls of therotor slot 68 such that upon rotation of the vane, the leading side wallof the vane will push against the opposed side wall of the rotor slotwhile permitting relative radial movement between the vane and the rotorslot. In this manner, rotation of the vane about the chamber axis willrotatably drive the rotor 22 about the rotor axis 49 within the pumpingchamber 30 while the vane moves radially relative to rotor. In theillustrated embodiment, surfaces of the vane and rotor function asbearing surfaces that provide the sliding engagement between the vaneand slot in the rotor. As will be appreciated, such sliding engagementcan be effected by other means such as the use of bearing devices, forexample roller bearings.

Any suitable means may be provided for transfer of rotary motion fromoutside the housing to the vane 26 for use of the rotary vane device asa compressor/pump, or for taking out rotary motion from the vane for useof the device as a motor. In the illustrated exemplary embodiment, oneend of the drive shaft 69 is extended to project axially from thehousing for coupling to an external device, such as a prime mover (e.g.electric motor, engine, etc.) or to a component to be driven by thedevice if used as a motor.

It can now be appreciated that the vane 26 is coupled to a vane drive,in particular the vane drive shaft 69, independently of the rotor 22 forrotation with the vane drive member about the pumping chamber axis. Thatis, vane is driven and the rotor follows the vane. This is in contrastto the conventional arrangement where the rotor is driven instead of thevane.

In the case where the vane 26 is fixed to the drive shaft 69 against anyrelative movement, the vane, during rotation about the pumping chamberaxis, will pivot relative to the rotor slot 68 while still drivinglyengaging the rotor. To accommodate this relative pivotal movement, therotor slot 68 in the rotor increases in width going from the radiallyouter end of the slot to a radially inner end of the slot.

If desired, a seal member may be provided at the radially outer end ofthe vane 26 for sealingly engaging the radially inner surface 42 of thehousing. The seal member may be a vane seal held and guided in a slot inthe end of the vane such that the vane seal can move radially relativeto the vane. The seal may be biased against the inner surfacesurrounding the pumping chamber or reliance can be had on centrifugalforce to cause the seal to be urged radially outwardly against the innersurface when the vane is rotated.

As will now be appreciated by those skilled in the art, the driving ofthe vane 26 rather than the rotor 22 will beneficially reduce the sideload acting on the vane, essentially to whatever is the bearing dragacting on the rotor that is rotatably driven by the vane. This leads toless power consumption, longer life, fewer stack-up tolerances betweenthe vane and housing, the ability to use plastic for the rotor and vanedue to the reduced loads, and/or fewer components. As noted, the rotorand vane can be made of plastic, such as a suitable nylon of PFEmaterial. For other applications, a carbon rotor and ceramic ballbearings can be used to stand up to corrosion associated with thehydrogen on board in fuel cells when the device is used as a compressorfor hydrogen recirculation. Another version may employ steel ballbearings, as when the device serves as a cathode air compressor, forexample in a fuel cell stack. In addition, many of the components can beformed from extrusions.

In operation, rotation of the vane 26 in a clockwise direction in FIGS.6-9 will cause fluid, such as a gas, to be drawn in from the port 35then functioning as an inlet port. This gas will flow into the expandingvolume space behind vane as the vane moves clockwise from its positionshown in FIG. 6. At the same time, the gas volume in front of therotating vane will be decreasing in size as the rotor vane assemblycontinues to rotate to its positions shown in FIGS. 7 and 8. When thepressure within the compressing volume ahead of the vane exceeds thepressure into which the compressed gas is to be discharged, the gas willflow out through the other port 34.

Although the invention has been shown and described with respect to acertain preferred embodiment or embodiments, it is obvious thatequivalent alterations and modifications will occur to others skilled inthe art upon the reading and understanding of this specification and theannexed drawings. In particular regard to the various functionsperformed by the above described elements (components, assemblies,devices, compositions, etc.), the terms (including a reference to a“means”) used to describe such elements are intended to correspond,unless otherwise indicated, to any element which performs the specifiedfunction of the described element (i.e., that is functionallyequivalent), even though not structurally equivalent to the disclosedstructure which performs the function in the herein illustratedexemplary embodiment or embodiments of the invention. In addition, whilea particular feature of the invention may have been described above withrespect to only one or more of several illustrated embodiments, suchfeature may be combined with one or more other features of the otherembodiments, as may be desired and advantageous for any given orparticular application.

1. A rotary vane device comprising: a housing including a pumpingchamber having an axis and flow passages for flow of fluid to and fromthe pumping chamber; a rotor eccentrically positioned in the pumpingchamber and supported in the housing for rotation about an axiseccentric to the pumping chamber axis whereby a variable volume space isformed between a radially outer surface of the rotor and a radiallyinner surface of the housing, the rotor having a radially extending slotopening to the radially outer surface of the rotor; a vane drive membersupported in the housing for rotation about the pumping chamber axis;and a vane disposed in the rotor slot and coupled to the vane driveshaft independently of the rotor for rotation with the vane drive memberabout the pumping chamber axis, the vane having a radially outer endadjacent the radially inner surface of the housing and a side wall forengaging an opposed side wall of the rotor slot while permittingrelative radial movement between the vane and the rotor slot, wherebyrotation of the vane about the chamber axis will rotatably drive therotor about the rotor axis within the chamber while the vane movesradially relative to rotor.
 2. A rotary vane device according to claim1, wherein vane drive member includes a drive shaft coaxial with thepumping chamber axis, and the vane is fixedly joined to the shaft andextends radially from the shaft.
 3. A rotary vane device according toclaim 1, wherein the rotor slot increases in width going from a radiallyouter end of the slot to a radially inner end of the slot, foraccommodating relative pivotal movement of the vane relative to the sidewall of the slot when the vane is rotatably driven about the pumpingchamber axis.
 4. A rotary vane device according to claim 2, wherein thevane is attached to the drive shaft by a pair of axially spaced apartvane supports fixed to the drive shaft for rotation with the driveshaft, and the vane extends axially between the vane supports.
 5. Arotary vane device according to claim 2, wherein the housing has axiallyspaced apart side walls defining respective axial ends of the pumpingchamber, and the drive shaft has opposite axial ends supported bybearings in the side walls, respectively.
 6. A rotary vane deviceaccording to claim 2, wherein the vane is radially outwardly spaced fromthe drive shaft.
 7. A rotary vane device according to claim 1, whereinthe rotor has opposite ends thereof supported by respective bearings inthe housing.
 8. A rotary vane device according to claim 7, wherein eachbearing includes an inner race, an outer race and anti-friction elementsbetween the inner and outer races.
 9. A rotary vane device comprising arotor and a vane positioned in a pumping chamber in a housing, whereinthe rotor has a rotor slot in which the vane is positioned,characterized by the vane being driven and the rotor following the vane.10. A rotary vane device according to claim 1, wherein the rotor slotincreases in width going from a radially outer end of the slot to aradially inner end of the slot, for accommodating relative pivotalmovement of the vane relative side wall of the slot when the vane isrotatably driven about the pumping chamber axis.
 11. A rotary vanedevice according to claim 1, wherein the housing has axially spacedapart side walls defining respective axial ends of the pumping chamber,and the rotor and vane are rotatably supported by respectiveeccentrically disposed bearings in each side wall.
 12. A rotary vanedevice according to claim 1, comprising a seal member at the radiallyouter end of the vane for sealingly engaging the radially inner surfaceof the housing.
 13. A rotary vane device according to claim 1, whereinthe housing includes a stator plate having a through bore forming thepumping chamber, and opposite end plates closing the ends of the pumpingchamber.
 14. A rotary vane device according to claim 1, wherein the vaneand rotor are about equal in longitudinal length
 15. A rotary vanedevice according to claim 1, wherein the rotor and vane are eachrotationally balanced.
 16. A rotary vane device according to claim 1,wherein the radially outer end of the vane is convexly curvedconcentrically with the pumping chamber axis.
 17. A rotary vane deviceaccording to claim 1, wherein the radially inner surface of the housingis curved concentrically around the pumping chamber axis.
 18. A rotaryvane device according to claim 1, wherein the radially outer surface ofthe rotor is curved concentrically around the rotor axis.